Methods and devices for adaptive scheduling request procedure

ABSTRACT

A method performed by a User Equipment (UE) includes a Medium Access Control (MAC) entity triggering a first Scheduling Request (SR) procedure for a first logical channel, triggering a second SR procedure for a second logical channel, and in response to triggering the first SR procedure, initiating a Random Access (RA) procedure and canceling the first SR procedure without cancelling the second SR procedure.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation application of U.S. patentapplication Ser. No. 16/197,394 filed on Nov. 21, 2018, which claims thebenefit of and priority to provisional U.S. Patent Application Ser. No.62/590,383 filed on Nov. 24, 2017. The contents of all above-namedapplications are fully incorporated herein by reference for allpurposes.

FIELD

The present disclosure generally relates to wireless communication, andmore particularly, to methods and devices for an adaptive SchedulingRequest (SR) procedure.

BACKGROUND

In a Long Term Evolution (LTE) wireless communication system, a UserEquipment (UE) may trigger a Scheduling Request (SR) procedure torequest the network to allocate uplink radio resources for transmissionwhen certain SR triggering condition(s) is satisfied. For example, ifthe UE has no uplink radio resources for transmitting the Buffer StatusReport (BSR) Medium Access Control (MAC) Control Element (CE), or doesnot receive a positive feedback (e.g., allocation of uplink radioresources for transmission) of the BSR from the base station, the UE maytrigger the SR procedure. Furthermore, once the SR procedure has failed,a Random Access (RA) procedure will be triggered, such that the pendingSR procedure is cancelled.

For the next generation (e.g., 5G New Radio (NR)) wireless communicationtechnology, the UE's Medium Access Control (MAC) entity can beconfigured with zero, one, or more than one SR configuration by a basestation (e.g., next generation NodeB (gNB)). Each SR configuration maycorrespond to one or more Logical Channels (LCHs), and each LCH may bemapped to zero or one SR configuration. If a UE triggers an SR procedurefor an LCH configured with an SR configuration, the UE may use the SRconfiguration to perform the SR procedure, which includes the SRtransmission via the uplink radio resource indicated by the SRconfiguration. That is, the SR configuration of the LCH that triggersthe BSR may be considered as the corresponding SR configuration for thetriggered SR procedure. However, the SR operation for the LCH with zeroSR configuration is still an open issue.

Thus, there is a need in the art for an adaptive SR procedure for LCH(s)configured with zero SR configuration in the next generation wirelesscommunication system.

SUMMARY

The present disclosure is directed to methods and devices for anadaptive SR procedure.

In an aspect of the present disclosure, a method performed by a UE isprovided. The method includes a MAC entity triggering a first SRprocedure for a first logical channel, triggering a second SR procedurefor a second logical channel, and in response to triggering the first SRprocedure, the MAC entity initiating an RA procedure and canceling thefirst SR procedure without cancelling the second SR procedure.

In another aspect of the present disclosure, a UE is provided. The UEincludes one or more non-transitory computer-readable media havingcomputer-executable instructions embodied thereon and at least oneprocessor coupled to the one or more non-transitory computer-readablemedia. The at least one processor is configured to execute thecomputer-executable instructions to trigger a first SR procedure for afirst logical channel, trigger a second SR procedure for a secondlogical channel, and in response to triggering the first SR procedure,initiate an RA procedure and cancel the first SR procedure withoutcancelling the second SR procedure.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the exemplary disclosure are best understood from thefollowing detailed description when read with the accompanying figures.Various features are not drawn to scale, dimensions of various featuresmay be arbitrarily increased or reduced for clarity of discussion.

FIG. 1 shows a schematic diagram of an SR configuration mapping, inaccordance with an implementation of the present disclosure.

FIG. 2 shows a schematic diagram of the SR configuration mapping withMAC entities assigned priority indices, in accordance with animplementation of the present disclosure.

FIG. 3A is a flowchart of a first option wherein an SR triggeringcondition is satisfied.

FIG. 3B is a flowchart of a second option wherein an SR triggeringcondition is satisfied.

FIG. 4 is a flowchart of a method performed by a UE for SR operation, inaccordance with an implementation of the present disclosure.

FIG. 5 is a flowchart of a method performed by a UE for SR operation, inaccordance with an implementation of the present disclosure.

FIG. 6 is a flowchart of a method performed by a UE for SR operation, inaccordance with an implementation of the present disclosure.

FIG. 7 is a flowchart of a method performed by a UE for SR operation, inaccordance with an implementation of the present disclosure.

FIG. 8 illustrates a block diagram of a node for wireless communication,in accordance with various aspects of the present application.

DETAILED DESCRIPTION

The following description contains specific information pertaining toexemplary implementations in the present disclosure. The drawings in thepresent disclosure and their accompanying detailed description aredirected to merely exemplary implementations. However, the presentdisclosure is not limited to merely these exemplary implementations.Other variations and implementations of the present disclosure willoccur to those skilled in the art. Unless noted otherwise, like orcorresponding elements among the figures may be indicated by like orcorresponding reference numerals. Moreover, the drawings andillustrations in the present disclosure are generally not to scale, andare not intended to correspond to actual relative dimensions.

For the purpose of consistency and ease of understanding, like featuresare identified (although, in some examples, not shown) by numerals inthe example figures. However, the features in different implementationsmay be differed in other respects, and thus shall not be narrowlyconfined to what is shown in the figures.

References to “one implementation,” “an implementation,” “exampleimplementation,” “various implementations,” “some implementations,”“implementations of the present application,” etc., may indicate thatthe implementation(s) of the present application so described mayinclude a particular feature, structure, or characteristic, but notevery possible implementation of the present application necessarilyincludes the particular feature, structure, or characteristic. Further,repeated use of the phrase “in one implementation,” or “in an exampleimplementation,” “an implementation,” do not necessarily refer to thesame implementation, although they may. Moreover, any use of phraseslike “implementations” in connection with “the present application” arenever meant to characterize that all implementations of the presentapplication must include the particular feature, structure, orcharacteristic, and should instead be understood to mean “at least someimplementations of the present application” includes the statedparticular feature, structure, or characteristic. The term “coupled” isdefined as connected, whether directly or indirectly through interveningcomponents, and is not necessarily limited to physical connections. Theterm “comprising,” when utilized, means “including, but not necessarilylimited to”; it specifically indicates open-ended inclusion ormembership in the so-described combination, group, series and theequivalent.

Additionally, for the purposes of explanation and non-limitation,specific details, such as functional entities, techniques, protocols,standard, and the like are set forth for providing an understanding ofthe described technology. In other examples, detailed description ofwell-known methods, technologies, system, architectures, and the likeare omitted so as not to obscure the description with unnecessarydetails.

Persons skilled in the art will immediately recognize that any networkfunction(s) or algorithm(s) described in the present disclosure may beimplemented by hardware, software or a combination of software andhardware. Described functions may correspond to modules may be software,hardware, firmware, or any combination thereof. The softwareimplementation may comprise computer executable instructions stored oncomputer readable medium such as memory or other type of storagedevices. For example, one or more microprocessors or general purposecomputers with communication processing capability may be programmedwith corresponding executable instructions and carry out the describednetwork function(s) or algorithm(s). The microprocessors or generalpurpose computers may be formed of applications specific integratedcircuitry (ASIC), programmable logic arrays, and/or using one or moredigital signal processor (DSPs). Although some of the exampleimplementations described in this specification are oriented to softwareinstalled and executing on computer hardware, nevertheless, alternativeexample implementations implemented as firmware or as hardware orcombination of hardware and software are well within the scope of thepresent disclosure.

A computer readable medium includes but is not limited to random accessmemory (RAM), read only memory (ROM), erasable programmable read-onlymemory (EPROM), electrically erasable programmable read-only memory(EEPROM), flash memory, compact disc read-only memory (CD ROM), magneticcassettes, magnetic tape, magnetic disk storage, or any other equivalentmedium capable of storing computer-readable instructions.

A radio communication network architecture (e.g., a long term evolution(LTE) system, a LTE-Advanced (LTE-A) system, or a LTE-Advanced Prosystem) typically includes at least one base station, at least one UE,and one or more optional network elements that provide connectiontowards a network. The UE communicates with the network (e.g., a corenetwork (CN), an evolved packet core (EPC) network, an Evolved UniversalTerrestrial Radio Access network (E-UTRAN), a Next-Generation Core(NGC), or an internet), through a radio access network (RAN) establishedby the base station.

A UE may include, but is not limited to, a mobile station, a mobileterminal or device, a user communication radio terminal, etc. Forexample, a UE may be a portable radio equipment, which includes, but isnot limited to, a mobile phone, a tablet, a wearable device, a sensor,or a personal digital assistant (PDA) with wireless communicationcapability. The UE is configured to receive/transmit signals over an airinterface from/to one or more cells in a radio access network.

A base station may include, but is not limited to, a node B (NB) as inthe UMTS, an evolved node B (eNB) as in the LTE-A, a radio networkcontroller (RNC) as in the UMTS, a base station controller (BSC) as inthe GSM/GERAN, an NG-eNB as in an E-UTRA base station in connection withthe 5GC, a next generation node B (gNB) as in the 5G-AN, and any otherapparatus capable of controlling radio communication and managing radioresources within a cell. The base station may connect to serve the oneor more UEs through a radio interface to the network.

The base station may be configured to provide communication servicesaccording to at least one of the following radio access technologies(RATs): Worldwide Interoperability for Microwave Access (WiMAX), GlobalSystem for Mobile communications (GSM, often referred to as 2G), GSMEDGE radio access Network (GERAN), General Packet Radio Service (GPRS),Universal Mobile Telecommunication System (UMTS, often referred to as3G) based on basic wideband-code division multiple access (W-CDMA),high-speed packet access (HSPA), LTE, LTE-A, eLTE (evolved LTE), NewRadio (NR, often referred to as 5G), and/or LTE-A Pro. However, thescope of the present application should not be limited to the abovementioned protocols.

The base station is operable to provide radio coverage to a specificgeographical area using a plurality of cells forming the radio accessnetwork. The base station supports the operations of the cells. Eachcell is operable to provide services to at least one UE within its radiocoverage. More specifically, each cell (often referred to as a servingcell) provides services to serve one or more UEs within its radiocoverage, (e.g., each cell schedules the downlink and optionally uplinkresources to at least one UE within its radio coverage for downlink andoptionally uplink packet transmissions). The base station cancommunicate with one or more UEs in the radio communication systemthrough the plurality of cells. A cell may allocate sidelink (SL)resources for supporting proximity service (ProSe). Each cell may haveoverlapped coverage areas with other cells.

As discussed above, the frame structure for NR is to support flexibleconfigurations for accommodating various next generation (e.g., 5G)communication requirements, such as enhanced mobile broadband (eMBB),massive machine type communication (mMTC), ultra-reliable communicationand low latency communication (URLLC), while fulfilling highreliability, high data rate and low latency requirements. The orthogonalfrequency-division multiplexing (OFDM) technology as agreed in 3GPP mayserve as a baseline for a NR waveform. The scalable OFDM numerology,such as the adaptive sub-carrier spacing, the channel bandwidth, and theCyclic Prefix (CP), may also be used. Additionally, two coding schemesare considered for NR: (1) low-density parity-check (LDPC) code and (2)Polar Code. The coding scheme adaption may be configured based on thechannel conditions and/or the service applications.

Moreover, it should be noted that in a transmission time interval (TTI)of a single NR frame, at least downlink (DL) transmission data, a guardperiod, and uplink (UL) transmission data should be included.Additionally, the respective portions of the DL transmission data, theguard period, and the UL transmission data should also be configurable,for example, based on the network dynamics of NR. In addition, sidelinkresource may also be provided in an NR frame to support ProSe services.

In various implementations of the present disclosure, the UE's MACentity may be configured with zero, one, or more SR configurations bythe base station. An SR configuration may include a set of PhysicalUplink Control Channel (PUCCH) resources for SR transmission indifferent Bandwidth Parts (BWPs) and/or cells. The set of PUCCHresources for SR transmission may be allocated in one or more BWPsand/or cells. For an LCH, at most one PUCCH resource for SR may beconfigured per BWP. Each SR configuration may correspond to one or morelogical channels (LCHs). Each LCH may be mapped to zero or one SRconfiguration. Such mapping may be configured by the base station (e.g.,gNB) through the Radio Resource Control (RRC) layer.

FIG. 1 shows a schematic diagram of an SR configuration mapping, inaccordance with an implementation of the present disclosure. As shown inFIG. 1, a MAC entity 100 of UE is configured with n SR configurations.Each SR configuration may include at least one SR-related parameter suchas an SR prohibit timer (e.g., sr-ProhibitTimer), a maximum number of SRtransmission (e.g., sr-TransMax) applied by the UE within an SRprocedure, and/or an SR transmission counter (e.g., SR_COUNTER).

More than one LCH may be configured with the same SR configuration. Asshown in FIG. 1, the SR configuration 2 (sr-ProhibitTimer², sr-TransMax²and SR_COUNTER²) are shared between LCH 2 and the LCH 3 since these twoLCHs are mapped to the same SR configuration (i.e., SR configuration 2).LCH x is mapped to SR configuration n. It should be noted that the LCH yis mapped to zero SR configuration, which means that LCH y may not beconfigured with any PUCCH resource for SR transmission and/or SR-relatedparameter by the base station (e.g., gNB).

In some implementations, the LCHs within a MAC entity may be assignedpriority indices and grouped into one or more Logical Channel Groups(LCGs).

As shown in FIG. 2, the UE's MAC entity 100 includes multiple LCHs 1 to6, which are assigned by priority indices of 4, 6, 3, 2, 1 and 5,respectively. The LCH 1 is configured with the SR configuration 1. TheLCHs 2 and 3 are configured with the SR configuration 2. The LCHs 4 and5 are configured with the SR configuration 3. The LCH 6 is configuredwith zero configuration because it is not configured with any SRconfiguration.

Also as shown in FIG. 2, the LCH 1 and the LCH 2 are grouped into theLCG 1, and the LCHs 3 to 6 are grouped into the LCG 2. In the example ofFIG. 2, an LCH with a lower priority index may have a higher priority.For example, the priority of the LCH 3 is higher than that of the LCH 2because the LCH 3 has a smaller priority index (e.g., 3) than that ofthe LCH 2 (e.g., 6). It is understood that the present disclosure is notlimited thereto. In other implementations, an LCH with a smallerpriority index may have a lower priority.

Referring to FIGS. 3A and 3B, a UE's MAC entity may need to handlesituations wherein a zero SR configuration LCH satisfies certain SRtriggering condition(s). One of the options (e.g., Option 1 shown inFIG. 3A) is to trigger the RA procedure directly once the SR triggeringcondition is satisfied. Another option (e.g., Option 2 shown in FIG. 3B)is to trigger the SR procedure when the SR triggering condition issatisfied, and keep the triggered SR procedure pending until it iscancelled.

As shown in FIG. 3A, the procedure of Option 1 includes actions 302 and304. In action 302, the SR triggering condition is satisfied. The SRtriggering condition may be, for example, the UE failing to acquireuplink radio resources for transmitting the BSR, or the UE not receivingany positive feedback (e.g., an allocation of uplink radio resources fortransmission) of the BSR from the base station. In action 304, the UEtriggers an RA procedure.

Option 1 is based on the RA triggering mechanism introduced in the LTEsystem; that the RA procedure is triggered after the SR procedure hasfailed (e.g., the UE has transmitted the SR for sr-TransMax times anddoes not get any uplink radio resource from the base station for BSRtransmission). The purpose of this mechanism is, after SR failure, tolet the UE ask the base station for a grant of uplink radio resourcethrough a Random Access Channel (RACH). However, it should be noted thatonce the RA procedure is triggered, the UE may release the PUCCHconfiguration, which means that other pending SR procedure(s) may alsobe cancelled.

Since the NR system is able to support multiple SR configurations withina single MAC entity and allow the MAC entity to perform more than one SRprocedure simultaneously, if all pending SR procedures are canceled oncean RA procedure is triggered, the system performance may be degraded.Furthermore, compared to other LCHs configured with the SRconfiguration, the zero SR configuration LCH may trigger the RAprocedure much earlier by skipping the sr-TransMax SR transmissions inother SR configurations.

In FIG. 3B, the procedure of Option 2 includes actions 332, 334 and 336.In action 332, the SR triggering condition is satisfied. In action 334,the UE triggers the SR procedure. In action 336, the UE keeps the SRprocedure pending until the SR procedure is cancelled. However, the basestation may prohibit the SR procedure(s) triggered for certain LCH(s)through an LCH SR masking mechanism (e.g., logicalChannelSR-Mask). Thebase station may not be aware that the zero SR configuration LCH hastriggered a SR, since the triggered SR is kept as pending throughout theprocess.

In various implementations of the present disclosure, an adaptive SRprocedure is provided for any LCH(s) (e.g., the LCH y in FIG. 1) thatare not configured with a valid PUCCH resource for SR transmission. Inone implementation, the LCH that is not configured with a valid PUCCHresource for SR transmission may refer to an LCH configured with a zeroSR configuration (zero SR configuration LCH). Specifically, since a basestation may transmit an SR configuration to a UE via an RRC message(e.g., an RRC reconfiguration message) to indicate to the UE where thePUCCH resource for SR transmission is, if an LCH is configured with zeroSR configuration, it also means that there is no valid PUCCH resourceconfigured for the LCH. In another implementation, the LCH that is notconfigured with a valid PUCCH resource for SR transmission may refer toan LCH that is configured with a PUCCH resource, but the PUCCH resourceis currently not in an active BWP.

In various implementations of the present disclosure, the UE's MACentity may trigger a first SR procedure for a first LCH that is notconfigured with a valid PUCCH resource for the first SR procedure, andperform a plurality of procedures after triggering the first SRprocedure. The procedures may include, for example, initiation of an RAprocedure and cancelation of the first SR procedure.

FIG. 4 is a flowchart of a method performed by a UE (e.g., by the UE'sMAC entity) for SR operation, in accordance with an implementation ofthe present disclosure. In the illustrated implementation, once the UEdetects that an LCH that is not configured with a valid PUCCH resourcesatisfies an SR triggering condition, the UE may trigger an SR procedurefor the LCH, and then initiate an RA procedure and cancel selected SRprocedure(s) triggered for specific LCH(s).

As shown in FIG. 4, the flowchart includes actions 402, 404, 406 and408. In action 402, the UE may detect that a first LCH that is notconfigured with a valid PUCCH resource for SR transmission satisfies anSR triggering condition. In one implementation, the SR triggeringcondition may be that a buffer status reporting (BSR) procedure hasfailed, such as the UE failing to obtain uplink radio resources fortransmitting a BSR MAC CE, or failing to receive a positive feedback(e.g., allocation of uplink radio resources for transmission) of the BSRfrom the base station.

In action 404, the UE may trigger (or initiate) a first SR procedure forthe first LCH. Once the first SR procedure is triggered, the first SRprocedure is considered as pending until it is cancelled. It should benoted that in the various implementations of the present disclosure, thetime at which an SR procedure (e.g., the first SR procedure) istriggered may refer to the time that the SR procedure enters the pendingstate, and not the time that an SR is actually transmitted. In such acase, even though the first SR procedure is triggered for the first LCH,the UE may not transmit an SR for the first LCH because the first LCH isnot configured with a valid PUCCH resource for the first SR procedure.

In action 406, the UE may trigger (or initiate) an RA procedure. Forexample, the RA procedure may be a 4-step procedure, which includes (1)uplink preamble transmission, (2) downlink Random Access Response (RAR)reception, (3) uplink RRC message transmission, and (4) downlink RRCmessage reception.

In action 408, the UE may cancel the pending SR procedure(s) triggeredfor specific LCH(s). According to various implementations of the presentdisclosure, the specific LCH(s) may be at least one of the following:

a) all of the LCH(s) within the same MAC entity (e.g., LCHs 1 to 6 inFIG. 2);b) all of the LCH(s) within the same LCG (e.g., LCHs 3 to 6 in FIG. 2);c) all of the LCH(s) having a lower priority than the zero SRconfiguration LCH (e.g., LCH 2 in FIG. 2);d) all of the LCH(s) having a higher priority than the zero SRconfiguration LCH (e.g., LCH 1, 3, 4 and 5 in FIG. 2);e) all of the LCH(s) that belong to an LCG containing at least one lowerpriority LCH than the zero SR configuration LCH (e.g., LCHs 1 and 2 inFIG. 2);f) all of the LCH(s) that belong to an LCG containing at least onehigher priority LCH than the zero SR configuration LCH (e.g., LCHs 1 to5 in FIG. 2);g) all of the LCH(s) that belong to an SR configuration containing atleast one lower priority LCH than the zero SR configuration LCH (e.g.,LCHs 2 and 3 in FIG. 2);h) all of the LCH(s) that belong to an SR configuration containing atleast one higher priority LCH than the zero SR configuration LCH (e.g.,LCHs 1 to 5 of SR configurations 1, 2 and 3);i) all of the LCH(s) having the same numerology mapping or requestingthe same type of numerology uplink radio resource; andj) the zero SR configuration LCH (e.g., LCH 6 in FIG. 2).

It should be noted that the zero SR configuration LCH described abovecan be replaced by an LCH (e.g., the first LCH) that is not configuredwith a valid PUCCH resource for the pending SR. For example, as shown inFIG. 3, the UE may initiate the RA procedure and cancel the first SRprocedure triggered for the first LCH after triggering the first SRprocedure.

FIG. 5 is a flowchart of a method performed by a UE (e.g., by the UE'sMAC entity) for SR operation, in accordance with an implementation ofthe present disclosure. In the illustrated implementation, once the UEdetects that an LCH that is not configured with a valid PUCCH resourcesatisfies an SR triggering condition, the UE may trigger the RAprocedure directly and cancel the pending SR procedure(s) triggered forspecific LCH(s).

As shown in FIG. 5, the flowchart includes actions 502, 504 and 506. Inaction 502, the UE detects that a first LCH that is not configured witha valid PUCCH resource for SR transmission satisfies an SR triggeringcondition. For example, the SR triggering condition may be that a bufferstatus reporting (BSR) procedure has failed.

Then in action 504, the UE triggers an RA procedure directly. In action506, the UE may cancel the pending SR procedure(s) triggered forspecific LCH(s). Examples of the specific LCH(s) can be the same as thatdescribed in action 408 of FIG. 4.

In some implementations, while the base station (e.g., gNB) mayconfigure an LCH without any SR configuration (i.e., a zero SRconfiguration), an additional Information Element (IE)“logicalChannelRA-Prohibit” may be appended to the LCH. This IE may havea Boolean value. For example, IE=“0” means that the LCH is allowed totrigger an RA procedure to further transmit the corresponding BSR MACCE, while IE=“1” means that an LCH (e.g., the LCH with zero SRconfiguration) is prohibited to trigger an RA procedure even though theLCH triggers an SR procedure. Once the SR procedure for the LCH istriggered, the SR procedure becomes pending and may be cancelled onlywhen other LCH(s) get uplink radio resources or trigger the RA proceduresuccessfully to further transmit the BSR MAC CE. In such a case, therequired uplink radio resource of the LCH may be appended to the BSR MACCE. The Core Network (CN) and the base station may coordinate with eachother to determine the setting of the IE “logicalChannelRA-Prohibit”based on the associated QoS flow for the LCH.

FIG. 6 is a flowchart of a method performed by a UE (e.g., by the UE'sMAC entity) for SR operation, in accordance with an implementation ofthe present disclosure. In the illustrated implementation, once the UEdetects that an LCH that is not configured with a valid PUCCH resourcesatisfies an SR triggering condition, the UE may trigger an SR procedurefor the LCH. The UE may further check whether a specific condition issatisfied. If the specific condition is satisfied, the UE may performfirst procedure(s) including, for example, keeping the SR procedurepending until it is canceled. If the specific condition is notsatisfied, the UE may perform second procedure(s) including, forexample, initiating an RA procedure and cancelling selected SRprocedure(s) triggered for specific LCH(s).

As shown in FIG. 6, the flowchart includes actions 602, 604, 606, 608,610 and 612. In action 602, the UE detects that a first LCH that is notconfigured with a valid PUCCH resource for SR transmission satisfies anSR triggering condition. For example, the SR triggering condition may bethat a buffer status reporting procedure has failed.

In action 604, the UE triggers a first SR procedure for the first LCH.

In action 606, the UE checks whether a specific condition is satisfied.According to various implementations of the present disclosure, thespecific condition may be one of the following:

1) there is no other pending SR procedure(s) triggered for the LCH(s)configured with SR configuration(s) within the same MAC entity (e.g.,LCH 1 to 5 in FIG. 2);2) there is no other pending SR procedure(s) triggered for the LCH(s)having a lower priority than the first LCH and configured with SRconfiguration(s) within the same MAC entity (e.g., LCH 2 in FIG. 2);3) there is no other pending SR procedure(s) triggered for the LCH(s)having a higher priority than the first LCH and configured with SRconfiguration(s) within the same MAC entity (e.g., LCHs 1, 3, 4 and 5 inFIG. 2); and4) there is no other pending SR procedure(s) triggered for the LCH(s)configured with SR configuration(s) within the same LCG (e.g., LCHs 3, 4and 5 in FIG. 2).

In action 608, if the specific condition is satisfied, the UE may keepthe first SR procedure pending.

In action 610, if the specific condition is not satisfied, the UE maytrigger an RA procedure.

In action 612, the UE cancels the pending SR procedure(s) triggered forspecific LCH(s). Examples of the specific LCH(s) can be the same as thatdescribed in action 408 of FIG. 4.

According to the illustrated implementation, since keeping the first SRprocedure pending means that the UE does not transmit any SR to the basestation for the first LCH, the uplink radio resource requirement for thefirst LCH may not be noticed by the base station. However, as long asany other pending SR procedure(s) are triggered for the LCH(s)configured with SR configuration(s) within the same MAC entity, the UEstill has the chance to be granted the uplink radio resource even thoughthe first LCH keeps quiet. For example, as shown in FIG. 1, once the LCHy triggers an SR procedure, the SR procedure may be kept pending becauseother LCH(s) 1 to x may have already triggered its (or their) SRprocedure(s).

FIG. 7 is a flowchart of a method performed by a UE (e.g., by the UE'sMAC entity) for SR operation, in accordance with an implementation ofthe present disclosure. In the illustrated implementation, once the UEdetects that an LCH that is not configured with a valid PUCCH resourcesatisfies an SR triggering condition, the UE may check whether aspecific condition is satisfied. If the specific condition is satisfied,the UE may perform first procedure(s) including, for example, triggeringan SR procedure for the LCH and keeping the SR procedure pending untilit is canceled. If the specific condition is not satisfied, the UE mayperform second procedure(s) including, for example, initiating an RAprocedure and cancelling selected SR procedure(s) triggered for specificLCH(s).

As shown in FIG. 7, the flowchart includes actions 702, 704, 706, 708,710 and 712. In action 702, the UE detects that a first LCH that is notconfigured with a valid PUCCH resource for SR transmission satisfies anSR triggering condition. For example, the SR triggering condition may bethat a buffer status reporting (BSR) procedure has failed.

In action 704, the UE checks whether a specific condition is satisfied.Action 704 may substantially be the same as (or correspond to) action606 of FIG. 6.

In action 706, if the specific condition is satisfied, the UE maytrigger a first SR procedure for the first LCH, and in action 708, keepthe first SR procedure pending.

In action 710, if the specific condition is not satisfied, the UE maytrigger an RA procedure, and in action 712, cancel the pending SRprocedure(s) triggered for specific LCH(s). Examples of the specificLCH(s) can be the same as that described in action 408 of FIG. 4.

In one implementation, the base station (e.g., gNB) may configure an RApending timer to a zero SR configuration LCH. The RA pending timer maybe configured by the base station on a zero SR configuration LCH basis.Once the zero SR configuration LCH triggers an SR procedure and pendsthe SR procedure, the RA pending timer is triggered. The SR proceduremay be kept pending while the RA pending timer is running. Once the RApending timer expires, the zero SR configuration LCH may trigger an RAprocedure and cancel the SR procedure(s) triggered for the specificLCH(s) as introduced in action 408 of FIG. 4, for example.

In another implementation, the RA pending timer is configured by thebase station (e.g., gNB) on a per MAC entity basis. Once the zero SRconfiguration LCH triggers an SR procedure and pends the SR procedure,the RA pending timer will be triggered if the RA pending timer is notrunning yet. If the RA pending timer has been running when the SRprocedure is triggered, all of the SR procedures triggered for each zeroSR configuration LCH may be kept pending before the RA pending timer isexpired. Once the RA pending timer expires, the UE may trigger an RAprocedure and cancel the SR procedure(s) triggered for the specificLCH(s) as introduced in action 408 of FIG. 4, for example. If the UEgets uplink radio resources to transmit the BSR MAC CE for the zero SRconfiguration LCH, the pending SR triggered for the zero SRconfiguration LCH can be canceled and the RA pending timer stopped. Itshould be noted that the zero SR configuration LCH described above canbe replaced by an LCH (e.g., the first LCH) that is not configured witha valid PUCCH resource for SR transmission.

FIG. 8 illustrates a block diagram of a node for wireless communication,in accordance with various aspects of the present application. As shownin FIG. 8, a node 800 may include a transceiver 820, a processor 826, amemory 828, one or more presentation components 834, and at least oneantenna 836. The node 800 may also include an RF spectrum band module, abase station communications module, a network communications module, anda system communications management module, input/output (I/O) ports, I/Ocomponents, and a power supply (not explicitly shown in FIG. 8). Each ofthese components may be in communication with each other, directly orindirectly, over one or more buses 834. In one implementation, the node800 may be a UE or a base station that performs various functionsdescribed herein, for example, with reference to FIGS. 1 through 7.

The transceiver 820 includes a transmitter 822 (e.g.,transmitting/transmission circuitry) and a receiver 824 (e.g.,receiving/reception circuitry), which may be configured to transmitand/or receive time and/or frequency resource partitioning information.In some implementations, the transceiver 820 may be configured totransmit in different types of subframes and slots including, but notlimited to, usable, non-usable and flexibly usable subframes and slotformats. The transceiver 820 may be configured to receive data andcontrol channels.

The node 800 may include a variety of computer-readable media.Computer-readable media can be any available media that can be accessedby the node 800 and include both volatile and non-volatile media,removable and non-removable media. By way of example, and notlimitation, computer-readable media may comprise computer storage mediaand communication media. Computer storage media includes both volatileand non-volatile, removable and non-removable media implemented in anymethod or technology for storage of information such ascomputer-readable.

Computer storage media includes RAM, ROM, EEPROM, flash memory or othermemory technology, CD-ROM, digital versatile disks (DVD) or otheroptical disk storage, magnetic cassettes, magnetic tape, magnetic diskstorage or other magnetic storage devices. Computer storage media doesnot comprise a propagated data signal. Communication media typicallyembodies computer-readable instructions, data structures, programmodules or other data in a modulated data signal such as a carrier waveor other transport mechanism and includes any information deliverymedia. The term “modulated data signal” means a signal that has one ormore of its characteristics set or changed in such a manner as to encodeinformation in the signal. By way of example, and not limitation,communication media includes wired media such as a wired network ordirect-wired connection, and wireless media such as acoustic, RF,infrared and other wireless media. Combinations of any of the aboveshould also be included within the scope of computer-readable media.

One or more presentation components 834 presents data indications to aperson or other device. Exemplary presentation components 834 include adisplay device, speaker, printing component, vibrating component, andetc.

The processor 826 (e.g., having processing circuitry) may include anintelligent hardware device, e.g., a central processing unit (CPU), amicrocontroller, an ASIC, and etc. (not explicitly shown in FIG. 8). Theprocessor 826 may include memory. The processor 826 may process the data830 and the instructions 832 received from the memory 828, andinformation through the transceiver 820, the base band communicationsmodule, and/or the network communications module. The processor 826 mayalso process information to be sent to the transceiver 820 fortransmission through the antenna 836, to the network communicationsmodule for transmission to a core network.

The memory 828 may include computer-storage media in the form ofvolatile and/or non-volatile memory. The memory 828 may be removable,non-removable, or a combination thereof. Exemplary memory includessolid-state memory, hard drives, optical-disc drives, and etc. Asillustrated in FIG. 8, The memory 828 may store computer-readable,computer-executable instructions 832 (e.g., software codes) that areconfigured to, when executed, cause the processor 826 to perform variousfunctions described herein, for example, with reference to FIGS. 1through 7. Alternatively, the instructions 832 may not be directlyexecutable by the processor 826 but be configured to cause the node 800(e.g., when compiled and executed) to perform various functionsdescribed herein.

From the above description, it is manifested that various techniques maybe used for implementing the concepts described in the presentapplication without departing from the scope of those concepts.Moreover, while the concepts have been described with specific referenceto certain implementations, a person of ordinary skill in the art wouldrecognize that changes may be made in form and detail without departingfrom the scope of those concepts. As such, the described implementationsare to be considered in all respects as illustrative and notrestrictive. It should also be understood that the present applicationis not limited to the particular implementations described above, butmany rearrangements, modifications, and substitutions are possiblewithout departing from the scope of the present disclosure.

What is claimed is:
 1. A method performed by a User Equipment (UE), themethod comprising: triggering, by a Medium Access Control (MAC) entity,a first Scheduling Request (SR) procedure for a first logical channel;triggering, by the MAC entity, a second SR procedure for a secondlogical channel; and in response to triggering the first SR procedure,initiating, by the MAC entity, a Random Access (RA) procedure, andcanceling, by the MAC entity, the first SR procedure without cancellingthe second SR procedure.
 2. The method of claim 1, wherein the firstlogical channel is not mapped to any SR configuration received by the UEfrom a base station through a downlink Radio Resource Control (RRC)message.
 3. The method of claim 1, wherein the first logical channel isnot configured with a valid Physical Uplink Control Channel (PUCCH)resource for the first SR procedure on an active Bandwidth Part (BWP).4. A User Equipment (UE) comprising: one or more non-transitorycomputer-readable media having computer-executable instructions embodiedthereon; and at least one processor coupled to the one or morenon-transitory computer-readable media, and configured to execute thecomputer-executable instructions to: trigger a first Scheduling Request(SR) procedure for a first logical channel; trigger a second SRprocedure for a second logical channel; and in response to triggeringthe first SR procedure, initiate a Random Access (RA) procedure, andcancel the first SR procedure without cancelling the second SRprocedure.
 5. The UE of claim 4, wherein the first logical channel isnot mapped to any SR configuration received by the UE from a basestation through a downlink Radio Resource Control (RRC) message.
 6. TheUE of claim 4, wherein the first logical channel is not configured witha valid Physical Uplink Control Channel (PUCCH) resource for the firstSR procedure on an active Bandwidth Part (BWP).